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package com.salesforce.dataloader.dao;

import java.util.List;

import com.salesforce.dataloader.exception.DataAccessObjectInitializationException;

/**
 * Data access object interface. Implementations should implement this for data sources such as CSV file, Database, etc.
 * This interface doesn't include actual access to data which is split into DataReader and DataWriter interfaces
 *
 * @author awarshavsky
 * @since before
 */
public interface DataAccessObject {

    /**
     * Function to provide any intialization of resources that we want to initialize after creation.
     *
     * @throws DataAccessObjectInitializationException
     */
    void open() throws DataAccessObjectInitializationException;

    /**
     * Check if the connection to data is valid. Throw an exception if not.
     *
     * @throws DataAccessObjectInitializationException
     */
    void checkConnection() throws DataAccessObjectInitializationException;

    /**
     * Close connections and free up resources on the data access object
     */
    void close();

    /**
     * @return List of columns names for the DAO
     */
    List<String> getColumnNames();

    /**
     * @return Current record number that has been read or written
     */
    int getCurrentRowNumber();
}
